Masks such as photomasks are typically used in photolithographic systems to define patterns on objects such as integrated circuits. The pattern defined on the object, however, may sometimes differ from the pattern of the mask. For example, optical diffraction may cause the pattern defined on an integrated circuit to differ from the pattern of the mask.
A mask pattern may be corrected to compensate for these deviations. According to a known technique for correcting a mask pattern, a pattern may be divided into segments. A correction value may be determined for each segment of the pattern, and the segments may then be updating according to the correction values. The known technique, however, may not be efficient in certain situations. It is generally desirable to be efficient in certain situations.